Photographic materials

ABSTRACT

Light-sensitive silver halide grains having an average size of up to 0.2 micron are sensitized with a noble metal sensitizer at a concentration of at least 50 mg. noble metal per mole of silver, and a sulfur sensitizer at a weight ratio of sulfur to noble metal of about 1:15 to 1:75; said silver halide grains being spectrally sensitized with a photographic spectral sensitizing methine dye.

United States Patent Millikan et al.

[ Aug. 21, 1973 PHOTOGRAPHIC MATERIALS [75] Inventors: Allan G. Millikan, Webster; Mary Jane W. Brizee, Pittsford, both of N.Y.

[73] Assignee: Eastman Kodak Company,

Rochester, N.Y.

[22] Filed: Aug. 13, 1970 [2!] Appl. No.: 63,606

[52] US. Cl 96/130, 96/127, 96/108 [51] Int. Cl G03c 1/28 [58] Field of Search 96/108, 127, 130

[56] References Cited UNITED STATES PATENTS 2,839,403 H958 Knott..... 96/127 3,573,920 /1971 Hiller 96/130 2,597,856 /l952 Damschroder 96/108 ll953 Damschroder et al. 96/108 2,642,361 2,448,060 ll948 Smith et a] 96/108 2,540,085 I195] Baldsiefen 96/108 Primary Examiner-Ronald H. Smith Assistant Examiner-Edward C. Kimlin Attorney-W. H. J. Kline, J. R. Frederick and O. H.

Webster [5 7] ABSTRACT 20 Claims, No Drawings PHOTOGRAPHIC MATERIALS This invention relates to photographic materials, and more particularly to fine grain silver halide photographic materials.

The combination of noble metal sensitizers and sulfur sensitizers has been suggested in the prior art for photographic silver halide emulsions. Typical disclosures of such sensitizers are made by Smith et al. in U.S. Pat. No. 2,448,060 isused Aug. 31, 1948, Baldsiefen U.S. Pat. No. 2,540,085 issued Feb. 6, 1951; Damschroder U.S. Pat. No. 2,597,856 issued May 27, 1952 and Damschroder et al. U.S. Pat. No. 2,642,361 issued June 16, 1953. Hiller in U.S. Pat. application Ser. No. 757,789 filed Sept. 5, 1968 now U.S. Pat. No. 3,573,920, and corresponding to Belgian Pat. No. 724,740 of Dec. 31, 1969, describes spectrally sensitized fine grain silver halide emulsions and states that such emulsions can be sensitized with sulfur and gold sensitizers. However, none of these references, nor any other reference known to applicants, suggest the sensitization of fine grain silver halide emulsions with a high concentration of noble metal sensitizer together with a low concentration of sulfur sensitizer.

Previously, it had been assumed that noble metal sensitization was most effective with large silver halide grains. Glafkides, Photographic Chemistry, published by the Fountain Press, London, 1958, states at page 320 that gold sensitization is mainly effective with large silver halide grains, which have higher sensitivity to light than fine silver halide grains (i.e., up to 0.2 micron in size). Glafkides also statesat page 319 that gold sensitization frequently results in substantial increases in fog and causes emulsion instability, which often results in the emulsion becoming useless after being kept for a few days.

Fine grain silver halide emulsions must be used instead of faster large grain silver halide emulsions for various purposes, for example in photographic applications where high resolution is essential, such as holography and microphotography. Hence,1it appears highly desirable to provide stable emulsions comprising fine silver halide grains which have low fog and high speeds.

One object of this invention is to provide photographic silver halide grains which exhibit increased speed to blue radiation.

Another object of this invention is to provide chemically sensitized photographic silver halide emulsions which are stable and exhibit increased speed to blue radiation. u

A further object of this invention is to providephotographic silver halide emulsions which are particularly useful in applications requiring high resolving power, such as holography and microphotography.

Still another object of this invention is to provide spectrally sensitized photographic silverhalide emulsions.

Another object of this invention is to provide spectrally sensitized fine grain silver halide emulsions having higher speeds in the region of spectral sensitivity.

Other objects of this invention will be apparent from this disclosure and the appended claims.

In accordance with this invention, light-sensitive silver halide grains having an average grain size up to about 0.2 micron are sensitized with the combination of a noble metal sensitizer, at a concentration of about at least 50 milligrams noble metal per mole of silver,

and a sulfur sensitizer at a weight ratio of sulfur to noble metal of about 1:15 to 1:75; and, the silver halide grains are spectrally sensitized with a photographic spectral sensitizing methine dye.

The combination of a high concentration of noble metal sensitizer and a low concentration of sulfur sensi tizer, together with a photographic spectral sensitizing dye, results in substantial and unexpected speed increases in the region of inherent sensitivity of silver halide grains. The increase in inherent sensitivity is accomplished without causing'high fog or emulsion instability.

Silver halide grains employed in the practice of this invention can comprise silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof. The silver halide grains can range in-size up to 0.2 micron, and preferably upto 0.15 or 0.1 pm. Grains in the range of about 0.02 up to 0.09 micron give excellent results. Such silver halide grains can be prepared by any of the well-known procedures. Very fine grain emulsions known in the art as Lippmann" emulsions are useful herein.

The noble metal sensitizers useful in this invention include the well-known gold sensitizers and other noble metals such as palladium and platinum, including any of the noble metal sensitizers described in Smith et al U.S. Pat. No. 2,448,060 issued Aug. 31, 1948. Typical useful gold sensitizers are described in Waller et al U.S. Pat. No. 2,399,083 issued Apr. 23, 1946, Baldesiefen U.S. Pat. Nos. 2,540,085 and 2,540,086 both issued Feb. 6, 1951; Damschroder U.S. Pat. No. 2,597,856 issued May 27, 1952 and Damschroder et al. U.S. Pat. No. 2,642,361 issued June 16, 1953. Illustrative addenda suitable for furnishing the noble metal moiety in I 03H AllClt a C=CH'-C is? Sa The noble metal sensitizer is employed in accordance with the invention in a concentration of from at least about 50 milligrams of noble metal per mole of silver, and preferably from about 125 to 175 milligrams noble metal sensitizer per mole of silver. Note that concentrations of noble metal are expressed in terms of noble metal and are not based on the total weight of the compound containing the noble metal. The noble metal sensitizer is employed at concentrations lower than which causes substantial fog, such as fog levels over 3. Generally, there is no advantage in employing over 200 mg. noble metal per mole of silver.

In accordance with the invention, the silver halide grains are chemically sensitized with a sulfur sensitizer. Sulfur sensitizers are well known in the art and are described, for example, by Damschroder et al. US. Pat. No. 2,642,36! issued June 16, I953, columns 3 and 4. Typical sulfur sensitizers contain a =C=S group or a -C- S-S-C- group. Typical sulfur sensitizers are thiourea, allylisothiocyanate, thiosinamine (allylthiourea), cystine and B-ethyl xanthate propionic acid. Also useful are methyl or ammonium thiocyanates, such as alkali metal thiocyanates (e.g., sodium or potassium thiocyanate) or alkaline earth metal thiocyanates (e.g., calcium thiocyanine, strontium thiocyanate, etc.), cadmium thiocyanate and ammonium thiocyanate. Especially useful are the alkali metal thiosulfates, preferably sodium or potassium thiosulfate, or ammonium thiosulfate. Thioureas, such as those referred to above, also produce particularly useful results.

Sulfur sensitizers are employed herein at a weight ratio of sulfur to noble metal of about 1:15 to l:75, and preferably about 1:30 to about 1:50. The amount of labile sulfur, not the entire weight of the compound containing the labile sulfur, is used in calculating the useful concentrations of sulfur. As will be apparent to those skilled in the art, certain sulfur sensitizers (e.g., sodium thiosulfate) contain two sulfur atoms, but only one of those sulfur atoms is labile. These compounds are used in concentrations calculated on the basis of the one labile sulfur atom therein.

Any methine (including polymethine) photographic spectral sensitizing dye can be employed in the practice of this invention. The most useful methine dyes are the cyanine, merocyanine, hemicyanine and hemioxonol dyes. The dyes can be used in widely varying concentrations, with optimum concentrations being determined by any suitable means previously described in the art. Generally, about to 2,000 mg. dye per mole of silver provide good results, although larger or smaller amounts produce useful results depending on the particular dye and silver halide used.

Typical useful cyanine dyes have the following general formula:

thiazole, 4-methylthiazole, 4-phenylthiazole, 5- methylthiazole, S-phenyl-thiazole, 4,5- dimethylthiazole, 4,5-diphenylthiazole, 4-(2- thienyl)thiazole, benzothiazole, 4-cholorbenzothiazole,

5 -chlorobenzothiazole -chlorobenzothiazole, 7- chlorobenzothiazole 4-methylbenzothiazole, 5 methylbenzothiazole, 6-methyl-benzothiazole, 5- bromobenzothiazole, o-bromobenzothiazole 5 phenylbenzothiazole, o-phenylbenzothiazole, 4-mathoxybenzothiazole, 5 -methoxybenzothiazole, 6- methoxybenzothiazole 5 -iodobenzothiazole, 6- iodobenzothiazole, 4-ethoxybenzothiazole, 5 ethoxybenzothiazole tetrahydrobenzothiazole, 5 ,6-

dimethoxy benzothiazole, 5,6-dioxymethylenebenzothiazole, S-hydroxy benzothiazole, 6- hydroxybcnzothiazole, naphtholZJ-dlthiazolc, naphtho[ 1,2-d1thiazole, 5-methoxynaphtho[2,3-dlthiazole, S-ethoxynaphthol2,3-d]thiazole, 8- methoxynaphthol2,3-d]thiazole, 7- methoxynaptho[2,3-d]thiazole, 4-methoxythianaphtheno7',6-4,5-thiazole, etc.; an oxazole nucleus, e.g., 4-methyloxazole, S-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5- dimethyloxazole, S-phenyloxazole, benzoxazole, 5- chlorobenzoxazole, S-methylbenzoxazole, 5- phenylbenzoxazole, o-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5- methoxybenzoxazole, S-methoxybenzoxazole, 5- ehlorobenzoxazole, methoxybenzoxazole, 5- hydroxybenzoxazole, 6-hydroxybenzoxazole, naph tho[2,1-d]oxazole, naptho[1,2-d]-oxazole, etc.; a selenazole nucleus, e.g., 4-methylselenazole, 4- phenylselenazole, benzoselenazole, 5- chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole, naphtho[2,l-dlselenazole, naphtho[1,2-d]selenazole, etc.; a thiazoline nucleus, e.g., thiazoline, 4-methylthiazoline, etc.; a pyridine nucleus, e.g., Z-pyridine, S-methyI-Z-pyridine, 4-pyridine,

3-methyl-4-pyridine, etc.; a quinoline nucleus, e.g., 2- quinoline, 3-methyl-2-quinoline, 5-ethyl-2-quinoline, 6-chloro-2-quinoline, 8-chloro-2quinoline, 6-methoxy- 2-quinoline, 8-ethoxy-2-quinoline, 8-hydroxy-2- quinoline, 4quinoline, 6-methoxy-4-quinoline, 7-methyI-4-quinoline, 8-chloro-4-quinoline, 1- isoquinoline, 3 ,4-dihydrol -isoquinoline, 3- isoquinoline, etc; a 3,3-dialkylindolenine nucleus, e.g., 3,3-dimethylindolenine, 3,3,S-trimethylindolenine, etc.; and, an imidazole nucleus, e.g., imidazole, 1- alkylimidazole, l-alkyl-4 phenylimidazo1e, l-alkyl-4,5- dimethylimidazole, benzimidazole, 1- alkylbenzimidazole, l-aryl-5,6-dichlorobenzimidazole, l-alkyll H-naphtho[ 1,2-d ]imidazole, l-aryl-3H- naphtho[ l ,2-d]imidazole, 1-alkyl-5-methoxy-l H- naphtho[l,2-d]imidazole, etc.; X represents an acid anion, such as chloride, bromide p-toluene sulfonate, methane sulfonate, methylsulfate, ethylsulfate, perchlorate, etc.; R I and R each represents an alkyl group (including substituted alkyl) having from 1 to 18, and

preferably one to four carbon atoms, such as methyl,

ethyl, propyl, isopropyl, butyl, sec-butyl, hexyl, dodecyl, octadecyl, benzyl, B-phenylethyl, sulfoalkyl such as B-sulfoethyl, -ysulfopropyl, 'y-sulfobutyl, 8-sulfobutyl, etc.; carboxyalkyl such as B-carboxyethyl, -y-carboxypropyl, d-carboxybutyl, etc.; sulfatoalkyl such as 'y-sulfoatopropyl and S-sulfatobutyl, etc. It will be noted that in some instances, the acid anion, represented by X in the above formula, is included in the substituent represented by R such as dyes containing the betaine type structurev Some specific cyanine dyes that can be used in the process of this invention include the following: l'3-diethylthia-2'-cyanine chloride 1, l -diethyl-2,2'-cyanine chloride 3,3'-diethyloxacarbocyanine iodide 5,5-dichloro-3,3 -diethylthiacarbocyanine iodide 1,1'-diethyl-2,2'-carbocyanine iodide 3,3'-diethylthiazolocarbocyanine iodide 3,3'-diethyl-4,4'-diphenylthiazolocarbocyanine iodide 6 3,3-diethyl-9-methylthiacarbocyanine iodide 1,3,3 triethylbenzimidazolo-oxac arbocyanine iodide 5 chloro-l ,3,3 '-triethylbenizimidazolooxacarbocyanine iodide 5,6-dichloro-l ,3,3 '-triethylbenzimidazolothiacarbocyanine iodide 1,1,3-triethylbenzimidazolo2'-carbocyanine iodide 1,1',3-triethy1benzimidazolo-40'-carbocyanine iodide 1,1-diethyl 2,4'-carbocyanine iodide 1, 3-diethyl-4-methylthiazol0-2'-carbocyanine iodide 3,3'-diethylthiadicarbocyanine iodide 1,1 '-diethyl-2,2'-dicarbocyanine iodide l,3-diethylthia-2-dicarbocyanine iodide Anhydro-5,5 ',6,6-tetrachlorol ,l ',3-triethyl-3 4- sulfobutyl)benzimidazolocarbocyanine hydroxide Anhydro-5,6-dichloro-b1-ethyl-3-(3-sulfobutyl)-3-(3- sulfopropyl )-4 ,5 '-benzobenzimidazolothiacarbocyanine hydroxide 1,1 ,',3 ,3 '-tetraethyl-naphtho[ l ,2- dlimidazolocarbocyanine iodide Anhydro-S ,6-dichloro-l ,3-diethyl-(3 '-sulfobutyl )benzimidazoloselenacarbocyanine hydroxide 1,2-diethylthia-4'-carbocyanine iodide Anhydro-5,5 ',6,6-tetrachloro-l ,1 -diethyl-3,3 '-di(4- sulfobutyl)benzimidazolocarbocyanine hydroxide Especially useful cyanine dyes include the carbocyanine, dicarbocyanine and tricarbocyanine dyes. Cyanine dyes which have at least one nucleus selected from a 5- or 6-dichlorobenzimidazole nucleus, a 5- or 6- methoxy-substituted benzothiazole nucleus or a 5- or 6-trifluoromethylbenzimidazole nucleus provide particularly good results. Supersensitization of these dyes with a sulfonated polynuclear aromatic organic supersensitizer, an azaindeneor a silver halide reducing agent (e.g., those described below) is sometimes advantageous.

A particularly useful class of cyanine dyes are tricarbocyanine dyes in which the meso carbon atom of the methine linkage of the dye is attached to the nitrogen atom of an amino group which forms an enamine with the methine linkage of the tricarbocyanine dye. The term tricarbocyanine denotes. dyeshaving the ammidinium-ion chromophoric system (see Mees and James, The Theory of the Photographic Process, Third Edition, 1966, page 201). Typically, such dyes have two nitrogen-containing heterocyclic nuclei which are joined by a straight chain methine linkage having seven methine groups. The carbon atom of the central methine group of the methine linkage is referred to herein as the meso carbon atom of the methine linkage.

The word enamine is used herein to refer to the group See Advances in Organic Chemistry, Methods and Results, Volume 4, Raphael, Taylor and Wynberg, 1963, Interscience, page 3, and Fieser and Fieser, Advanced Organic Chemistry, Reinhold Publishing Corp., 1961, pages 494-499.

The preferred enamine tricarbocyanine dyes-used herein have the following formula:

wherein a and b each represents an integer of from 1 to 2; X represents an acid anion, such as those mentioned above; R and R each represents a value given for R and R above; Z and Z are each selected from a value given for Z and Z above; Q represents a divalent linkage, such as ethylene, trimethyl, orthophenylene, which linkage can be substituted, for example, with halogen, an alkyl or an alkoxy group of one to four carbon atoms; and R and R taken separately each represents a member selected from the group consisting of alkyl and aryl, and, taken together R and R represent the non-metallic atoms required to complete a heterocyclic ring containing from 5 to 6 atoms, e.g., a morpholino group, a thiomorpholino group, a piperidino group, a piperazinyl group, (preferably a 4-alkyl-lpiperazinyl group such as methyl, ethyl, ethoxycarbonyl, propyl or butyl groups, or an 4-aryl-l-piperazinyl group such as a 4-phenyl-l-piperazinyl group) a pyrrolidinyl group, an indolinyl group, a tetrahydroquinoyl group and a decahydroquinoyl group. Especially good results are obtained when Z and Z each represents a benzoxazole, a naphthothiazole nucleus, or a benzothiazole nucleus; Q represents an ethylene linkage; and, R and R are taken together and represents a piperazinyl group, 4-ethoxycarbonyl-l-piperazinyl being preferred.

Typical specific enamine tricarbocyanine dyes useful in the practice of this invention are set out in Table A below:

TABLE A Anhydro-lldibut lamino-l0, 12'et ylene-3,3- di(3-sulfopropyl) thiatricarbocyanine hydroxide, soldium salt III VII

VIII

XII

3,3-DiethyI-l0,l 2-ethylene-l l-( lpyrrolidinyl )-thiatricarbocyanine iodide l0,l2-ethylene-l ,I 3,3,3,

3 '-hexamethyl-l l-( l-pyrrolidinyl)indotricarbocyanine iodide 3,3-Diethyl-l0,lZ-ethyIene-l Lpiperidion thiatricarbocyanine iodide 3 ,3 '-Diethyll 0,1 2

-ethylene- I morpholinothiatricarbocyanine iodide 3 ,3 '-Diethyl-l I-piperidino-IO, l 2- trimethylenethiatricarbocyanine iodide 3,3'-Diethyl-l0,12-ethylene-lI-(l-lidolinyl)oxatricarbocyanine perchlorate XIII XIV

XVI

3,3'-Diethyl-IO,l2-ethylene-l l-[l,-(1.2,3.4-

tetrahydroquinolyl loxyatricarbocyanine perchlorate I l-Diethylamine-3,3'diethyl-l0,l2-ethylenethriatricarbocyanine perchlorate l l -Diethylan1ino l 0, l 2-ethylene- 1,1 I ,3,3',3 '-hexamethylindrotricarbocyanine perchlorate 3,3-Diethyl-l0,l2-ethylenel l-[ l-( 1 ,2,3,4

tetrahydroquinolyl)]4,5,;4,5'-dibenzothiatricarbocyanine perchlorate l l-Diphenylamino3,3 diethyl-l0,l2-

ethyleneoxatricarbocyanine perchlorate l l-Dimethylamino-3,3'-diethyl-l0,12-

ethylenethiatricarbocyanine perchlorate 3,3'-Diethyl-l0,l2-trimethylene-l lthiomorpholinooxathiatricarbocyanine perchlorate 3,3'-Diethyl-I0,l2-ethylene-l I l-decahydroquinoly)-4,4'- tricarbocyanine perchlorate Anhydro-l l-(4ethoxycarbonylpiperazinl yl)-l0,l2-ethylene-3,3-bis( 3sulfopropyl)- 5,6;5 ,6-dibenzothiatricarbocyanine hydroxide, triethylamine slat XVII XVIII XIX XXI

XXII

XXIII XXIV XXV

The enamine tricarbocyanine dyes employed in this invention can be prepared by reacting one mol of an intermediate having formula III below:

to obtain a compound having formula V below:

One mol of the compound of formula V above can then be reacted with one mol of a compound having formula VI below:

to obtain a compound having formula II above. In the above formulas, X,, a, b, 2,, 2;, Q, R R R, and R have the meanings given above. The reactions are advantageously conducted in a suitable solvent, such as acetone or acetic anhydride, and preferably in the presence of a basic condensing agent, such as triethylamine, and at elevated temperatures, such as the refluxing temperature of the reaction mixtures. Further details on the preparation of dyes employed in this invention appear in .Ieffreys U.S. Pat. application Ser. No. 314,864 filed Oct. 10, I963 U.S. Pat. No. 3483195 and corresponding French Pat. No. 1,410,864; .Ieffreys US. Pat. application Ser. No. 518,0l filed Jan. 3, 1966 US. Pat. No. 3506655, and corresponding Belgian Pat. No. 674,800; Fumia et al. US. Pat. application Ser. No. 574,947 filed Aug. 25, 1966 Pat. No. 3482978 and corresponding Belgian Pat. No. 702,840; and, Fumia et al. US. Pat. application Ser. No. 860,395 filed Sept. 23, 1969 now abandoned, and entitled Sensitizing Dyes and Photographic Emulsions and Elements Containing Said Dyes," and continuation-impart application thereof US. Pat. Ser. No. 22,708 filed Mar. 25, 1970 Pat. No. 362388l. Supersensitization of these dyes with a sulfonated polynuclear aromatic organic supersensitizer, an azaindene or a silver halide reducing agent is described by Hiller et al in US. Pat. application Ser. No. 860,394 filed Sept. 23, 1969 now abandoned.

Merocyanine dyes are effectively employed in the practice of this invention. Typical useful merocyanine dyes have the following formula:

wherein R-,, L and Z, represents a value selected from those given above for R,, L and Z, respectively; c represents an integer of from 1 to 2; p represents an integer of from 1 to 3; and, Q represents the non-metallic atoms necessary to complete a 5- or 6-membered nucleus of the type used in merocyanine dyes typically containing a hetero atom selected from nitrogen, sulfur, selenium, and oxygen, such as a 2-pyrazolin-5-one nucleus, e.g., 3-methyl-l-phenyl-2-pyrazolin-S-one, l-phenyl-2-pyrazoline-5-one, l-(2-benzothiazolyl)-3- methyl-2-pyrazolin-5-0ne, etc.; an isoxazolone nucleus, e.g., 3-phenyl-5(4H)-isoxazolone, 3-methyl-5(4H) -isoxazolone, etc.; an oxindole nucleus, e.g., l-alkyl-2- oxindoles, etc.; a 2,4,6-triketohexahydropyrimidine nucleus, e.g., barbituric acid or 2-triobarbituric acid as well as their l alkyl (e.g., l-methyl, l-ethyl, l-propyl, l-heptyl, etc.) or l,3-dialkyl(e.g., 1,3-dimethyl, 1,3- diethyl, 1,3-dipropyl, 1,3-diisopropy], 1,3-dicyclohexyl, l,3-di(B-methoxyethyl), etc.; or 1,3-diaryl (e.g., 1,3- diphenyl, 1,3-di-(p-chlorphenyl), l,3-di(p-ethoxycarbonylphenyl), etc.); or Laryl (e.g., l-phenyl, l-pchlorophenyl, 1-p-ethoxycarbonylphenyl), etc.) or 1- alkyl-3-aryl (e.g., l-ethyl-3-phenyl, l-n-heptyl-3- phenyl, etc.) derivatives; a rhodanine nucleus (i.e., 2-thio-2,4-thiazolidinedione series), such as rhodanine, 3-alkylrhodanines, e.g., 3-ethylrhodanine, 3- allylrhodanine etc., 3-carboxyalkylrhodanines, e.g., 3-(Z-carboxyethyl)rhodanine, 3-(4-carboxybutyl)- rhodanine, etc., 3-sulfoalkylrhodanines, e.g., 3-(2-sulfoethyl)rhodanine, 3(3-sulfopropyl)rhodanine, 3-(4-sulfobutyl)rhodanine, etc., or 3- arylrhodanines, e.g., 3-phenylrhodanine, etc., etc.; a 2(3H)imidazo[l,2-a]pyridone nucleus; a 5,7-dioxo- 6,7-dihydro-5-thiazolo[3,2-a1pyrimidine nucleus, e.g.,

5,7-dioxo-3-phenyl-6,7-dihydro-5-thiazolo[3,2-a]- pyrimidine, etc.; a 2-thio-2,4-oxazolidinedione nucleus (i.e., those of the 2-thio-2,4(3H, 5H)-oxazoledione series) e.g., 3-ethyl-2 -thio-2,4-oxazolidinedione, 3-(2- thianaphthenone, etc.; a 2-thio-2,S-thiazolidinedione nucleus (i.e., the 2-thio-2,5-(3H,4H)-thiazoledi0ne seimidazolidinedione, v l,3-diethyl 2,4- imidazolidinedione, l-ethyl-3-phenyl-2,4- imidazolidinedione, l-ethyl-3-a-naphthyl-2,4- imidazolidinedione, l,3-diphenyl-2,4- imidazolidinedione, etc; a 2-thio-2,4- imidazolidinedione (i.e., 2-thiohydantoin) nucleus,

e.g., 2-thio-2,4-imidazolidinedione, 3ethyl-2-thio-2,4-

imidazolidinedione, 3-(4-sulfobutyl)-2-thio-2,4- imidazolidinedione, 3-( 2-carboxyethyl)-2-thio-2,4- imidazolidinedione, 3-phenyl-2-thio-2,4- imidazolidinedione, 3-a-naphthyl'2-thio-2,4- imidazolidinedione, l,3diethyl-2-thio-2,4- imidazolidinedione, 1-ethyl-3-phenyl-2-thio-2,4- imidazolidinedione, l-ethyl-3-a-naphthyl-2-thio-2,4- imidazolidinedione, l,3diphenyl-2-thio-2,4- imidazolidinedione, etc.; a Z-imidazolin-S-ohe nucleus,

e.g., 2-propylmercapto-2-imidazolin-S-one, etc.; etc. (Especially useful are nuclei wherein Q represents the non-metallic atoms required to complete a heterocyclic nucleus containing five to six atoms in the heterocyclic ring, three to four of said atoms being carbon, and two of said atoms being selected from the group consisting of nitrogen, oxygen, and sulfur, and at least one of said two atoms being a nitrogen atom. Typical useful merocyanine dyes are described in Brooker et al. US. Pat. No. 2,493,747 and 2,493,748, both issued Jan. 10, 1950, and Knott US. Pat. No. 2,839,403 issued June 17, 1958.

Another preferred class of methine dyes include those comprising first and second! nuclei joined by a double bond or methine linkage (including one or more methine groups); the first of said nuclei being selected from the groupd consisting of l a nitrogen-containing heterocyclic nucleus of the type used in cyanine dyes having from 5to 6 non-metallic atoms in the heterocyclic ring, and (2) a nitrogen-containing heterocyclic ketomethylene nucleus of the type used in merocyanine dyes having from 5 to 6 non-metallic atoms in the heterocyclic ring, joined in each instance by a carbon atom of l) or (2) to said linkage; and said second nucleus being an enamine group selected from the group consisting of a l-(3,4,4a,5,6,7-hexahydro-2-naphthyl)- pyrrolidine group, a l-(3,3a,4,5-tetrahydro-2H-inden- 6-yl)pyroldine group, a l-(2-nonb0rnylidene)pyrroline group and a l-( l-indanylidene)pyrrolidine group, joined at a carbon atom thereof to said linkage, to complete said dye. Preferred dyes of this type include those represented by the following formulas:

vm. z,

and

and

which groups can be further substituted on appropriate nuclear carbon atoms thereof by alkyl, e.g., methyl, butyl, etc., or alkoxy, e.g., methoxy, butoxy, etc., and the like; R X, and Q represents a value given above for R,, X and Q, respectively. Methine dyes of this type can be conveniently prepared in a number of ways. For example, a number of the dyes defined by formula VIII above are advantageously prepared by heating a mixture of l a heterocyclic salt of the formula:

whereinfis 2 or 3; e, L, R X and Z are as previously defined, and R, represents a hydrogen atom or an acyl group, e.g., acetoxy, phenoxy, etc., with (2) an enamine intermediate selected from the group consisting of a l(3,4,4a,5,6,7-hexahydro-2-naphthyl)pyrrolidine,

LII

or a l 3.3a,4.5-tetrahydrt2H-inden-(ryllpyrrolidonc. or a l-(2-norbornylidene)pyrrolidinium salt, e.g., the chloride, bromide, iodide, perchlorate, p-toluenesulfonate, etc. salt, or a 1-( l-indanylidene)pyrrolidinium salt, e.g., the chloride, bromide, iodide, perchlorate, p-toluenesulfonate, etc. salt, in approximately equimolar proportions, in a solvent medium such as ethanol, pyridine, N,N-dimethylacetamide, acetic anhydride, etc. Advantageously, a basic condensing agent such as triethylamine is used with the acetic anhydride reaction medium. The dyes are then separated from the reaction mixtures and purified by one or more recrystallizations from appropriate solvents such as methanol, mixtures of pyridine and methanol, and the like. The dyes wherein the value offis 1 in formula VI" above are advantageously prepared with l) a heterocyclic salt of the formula:

wherein g, R X and Z are as previously defined and R represents an alkyl or aryl group, e.g., methyl, butyl, phenyl, etc., and (2) an enamine intermediate above defined, under generally similar reaction conditions and purification of the dyes as described in the preceding procedure. The dyes defined by formula [V above are also prepared by the above procedure described for the dyes of formula Vlll using the same enamine intermediates except that the heterocyclic salt of formula X is replaced by a ketomethylene heterocyclic compound of the formula:

XII.

wherein g, L, R and Q, are as previously defined. Dyes of this type are described in Fumia et al. U.S. Pat. application Ser. No. 830,483 filed June 4, 1969, and include such dyes as 3- ethyl-2- {2-[213 ,4,4a,5.6-hexahydro-7-( l -pyrrolidinyl) 1 naphthyllvinyl} benzoxazolium iodide; 3-ethyl-2- {2-[2,3,4,4a,-5,6-hexahydro-7-(lpyrrolidinyl)-lnaphthyllv inyl} benzothiazolium iodide; 3-ethyl-5- {[2 ,3 ,4 ,4a,5 ,6-hexahydro-7-(l-pyrrolidinyl)-lnaphthyl]methylene} rhodanine; 3-ethyl-2-[2,6,7,7atetrahydro-5-( l-pyrrolidinyl)-3-indenyl]benzothiazolium perchlorate; 3-ethyl-2- {2-[2 ,6 ,7 ,7a-tetrahydro-5-( l -pyrrolidinyl)-3- indenyl]-vinyl} benzoxazolium iodide; 3-ethyl-2- {2-[2,6,7,7a-tetrahydro-5-(l-pyrrolidinyl)- 3 inde nyl ]vi nyl} benzothiazolium iodide; 3-phenyl-4- {[2,6].7a-tetrahydro-5-(l pyrrolidinyl)-3-indenyl]- methylene} V -2-isoxazolin-5-one; 3-methyl-l-phenyl-4- [2 ,6,7 ,7a-tetrahydro-5-( l -pyrrolidinyl)-3- 5 {benzoxazolium perchlorate; 3-ethyl-2- 2-[3-(l pyrrolidinyl)-2-norbomen-2-yl]vinyllbenzothiazolium perch orate; V l-ethyl-Z- {2-[3-(lpyrrolidinyl)-2-norbomen-2-yl]vinyl} 13 naphtholl .2-dlthiazolium perchlorate; 1,3,3- trimethyl-2- 2-[3-( l pyrrolidinyl)-2-indenyl]vinyl}- 3I-I-indolium perchlorate: 3-ethyl-2- 2-[3-( l pyrrolidinyl)-2-indenyl]vinyl}- benzoxazolium perchlorate; 3-ethyl-2- 5 {2-[3-(1-pyrrolidinyl)-Z-indenyllviny|} benzothiaioliim perchlorate and l-ethyl-2- Still other useful dyes of this class have the following formula:

XIII.

wherein 0, represents a value selected from those given for Q, above and D, represents a group having the following formula:

CH: CHI

Enamine dyes containing a double bond remote from the chromophoric chain can be prepared in a manner similar to the preparation of the enamine dyes of formulas ll, VIII and IX above, but using one of the following starting materials:

Intermediate A l-cyclopentylidene-3-pyrrolinium perchlorate 3-Pyrrolinium perchlorate (17.0 g) and 3-pyrroline (4 drops) are suspended in-ethanol ml) and the suspension heated on a steam bath to obtain a solution. Cyclopentanone (l0.l g) is then added to the hot solution and solid precipitated. The mixture is heated to reflux and then chilled. The solid is collected on a filter and the yield is 22.5 g percent), m.p. 202-203 C.dec.

Intermediate B 1-Isopropylidene-3-pyrrolinium perchlorate 6 :N: om-ii-cn, (:10.

A solution of 3-pyrroline (14.5 g) in ether (1.1) is treated with 72 percent perchloric acid (28.0 g) with stirring and cooling. Decanted, stirred residue with a fresh portion of ether (1 l.), decanted and then suspended the residue in ethanol ml). Acetone (l 1.6 g) is added, the mixture is heated to refluxand then chilled. The solid is collected on a filter and then recrystallized from ethanol. The yield is 28 g (67 percent), m.p. l68-l69 C dec. In preparing dyes from this compound, it is necessary to have acetic anhydride present which indicates that the compound may be a hydrate. Intermediate C Cyclopen'tenylidenediallylammonium perchlorate emot Cyclopentanone (25.2 g), diallylamine (49.0 g), ptoluene sulfonic acid (0.5 g) and benzene (90 ml) are placed in an apparatus designed for the continuous removal of water and heated at reflux for 16 hours. After evaporation under reduced pressure, the residue is distilled in vacuum to yield the enamine (b.p. -93 C/lS mm Hg). The enamine so obtained is dissolved in ether (1 l.), and the cooled solution treated with 72 percent perchloric acid until the mixture is just acid. Decanted, stirred residue with a fresh portion of ether (1 l.), decanted and then recrystallized the solid from ethanol. The yield is 42.8 g (54 percent), m.p. l22-l23 C dec.

l Intermediate D 1-(5,5-Dimethyl-3-methylene-1- cyclohexen- 1-yl)-3-pyrroline HIC CH;

lsophorone (41.4 g), 3-pyrroline (31.0 g), p-toluene sulfonic acid (0.5 g) and benzene (90 ml) are placed in an apparatus designed for the continuous removal of water and heated at reflux for 1 hour. After evaporating under reduced pressure, the residue is distilled in vacuum. Decomposition takes place during the distillation with 12.1 g (21 percent) of the desired material being obtained. (b.p. 89-95 C/0.4-1.1mm Hg) Intermediate E 5,5-Dimethyl-3-(3-pyrrolin-l-yl)-2- cyclohexen-l-one 1110 CHI 5,5-Dimethyl-l,3-cyclohexanedione (28.0 g), 3- pyrroline (15.2 g) and benzene (250 ml) are placed in an apparatus designed for the continuous removal of water and heated at reflux for 1 hour. The mixture is then evaporated, under reduced pressure, to a volume of 100 ml. The residue is diluted to -400 ml with ligroine (b.p. 35-60) and the mixture chilled. The solid is collected on a filter and the yield is 37.5 g(96 percent), m.p.=111-112 C. dec. Intermediate F 1-(3-Chloro-5,5-dimethyl-2- cyclohexen- 1 -ylidene-3-pyrrolinium perchlorate H1O CH:

To a solution of 5,5-dimethyl-3-(3-pyrrolin-l-yl)-2- cyclohexen-l-one (37.5 g) in benzene (300 ml) is added phosphorous pentachloride (40.8 g). The mixture is heated to reflux and then removed from heat until the initial reaction has subsided. The reaction is then heated at reflux for 2 hours. After cooling, the mixture is stirred with ice water (-300 ml). The water layer is removed and an aqueous solution of sodium perchlorate (36 g/- 100 ml) is added to it. After chilling, the solid is collected on a filter and dried. The

crude yield is 40.5 g (67 percent). After one recrystalli zation from ethanol, the yield is 29.5 g (49 percent), m.p. 140141 C dec.

Intermediate G l-cyclopentylidene-l,2,5,6- tetrahydropyridinium perchlorate 1-Cyclopentylidene-3-pyrrolinium perchlorate (1.3 g), 2-(2-acetanilidovinyl)-3-cthylbenzoxazolium iodide (2.2 g), and triethylamine (1.5 ml) are dissolved in acetic anhydride (15 ml) and stirred at room temperature for 15 minutes. The solidis collected on a filter and,

after two recrystallizations from methanol, the yield of purified dye is 0.5 g (25 percent), m.p. 262-263 C dec.

3,3 '-Diethyl-10,12-ethylene-1 1-(3-pyrrolin- 1 -y1)oxatricarbocyanine perchlorate 1-Cyc1opentylidene-B-pyrrolinium perchlorate 1.2 g), 2-(2-acetanilidovinyl)-3-ethy1benzoxazolium iodide (4.8 g), and triethylamine (1.5 ml) are dissolved in acetic anhydride (15 ml) and heated at reflux for 10 minutes. After cooling to room temperature, the solid is collected on a filter, washed with methanol and then recrystallized from cresol/methanol. The yield of purified dye is 0.5 g (22 percent), m.p. 267-268 C dec. 3-Ethyl-2-[4-(3-pyrrolin-l-yl)-1 ,3-pentadienyl1benzoxazolium perchlorate l-Ispropylidene-B-pyrrolinium perchlorate (2.3 g), 2-( 2-acetanilidovinyl )-3-ethylbenzoxazolium iodide (4.3 g), acetic anhydride (1.0 ml) and triethylamine (1.7 ml) are dissolved in ethanol (20 ml) and heated at reflux for minutes. After chilling, the solid is collected on a filter and then recrystallized from methano]. The yield of purified dye is H g (29 percent), m.p. 223-224 C dec. 3-Methyl-2-[4(3-pyrrolin-l-yl)-l,3- pentadienyl lthiazolium perchlorate l-lsopropylidene-3pyrrolinium perchlorate (2.3 g), 2-(2-anilinovinyl)-3-methyl-2thiazolium iodide (3.5 g), acetic anhydride (2.0 ml), and triethylamine (3.4 ml) are dissolved in acetonitrile ml) and heated at reflux for 10 minutes. After chilling, the solid is collected on a filter and then recrystallized from methanol. The yield of purified dye is 1.2 g (36 percent), m.p. 223-224 C dec. 2-[ 2-( 2-Diallylaminol *cyclopentenyl )vinyl]-3-ethylbenzothiazolium perchlorate AH 5H CHa CI Il ciot Cyclopentenylidenediallylammonium perchlorate (2.9 g), 2-(2-acetanilidovinyl)-3-ethylbenzothiazolium iodide (4.5 g) and triethylamine (1.4 ml) are dissolved 5-Acetanilidomethylene-3-ethylrrhodanine (3.06 g), cyclopentenylidenediallylammonium perchlorate (2.64 g) and triethylamine (1.5 ml) are dissolved in N,N- dimethylacetamide (15 ml) and heated at a gentle reflux for 5 minutes. The reaction mixture is diluted to 300 ml with boiling methanol and, after chilling, the dye is collected on a filter. The yield is 0.40 (12 percent), m.p. l27l28 C dec. 3-Ethyl-2-[4,6-neopentylene-6-( 3-pyrrolinl -yl l ,3 ,5 hexatrienyl]benzothiazolium iodide H10 OH:

H :Hs I e i-(5,S-Dimethyl-S-methylenel -cyclohexeni -yl )-3- pyrroline (1.0 g) and 2-(2-acetanilidovinyl)-3-ethylbenzothiazolium iodide (2.3 g).are dissolved in ethanol (15 ml) and heated at reflux for 5 minutes. After chilling, the solid is collected on a filter and dried. The crude yield is 1.4 g (56 percent). After one recrystalli zation from methanol, the yield of purified dye is 1.1 g (44 percent), m.p. 233234 C dec. 1,3 ,3-Trimethyl-2-[ 4,6-neopentylene-6-( 3-pyrrolinl y])-l ,3,5-hexatrienyl]-3H-indolium perchlorate l-(5,5-Dimethyl-3-methylene-l-cyclohexen-l-yl)-3- pyrroline (1.0 g) and 2-( 2-acetanilidovinyl)-l,3,3- trimethyl-BH-indolium iodide (2.2 g) are dissolved in ethanol (15 ml) and heated at reflux for 5 minutes. An aqueous solution of sodium perchlorate (1.0 g/-5 ml) is added and, after chilling, the crude dye is collected on a filter. After one recrystallization from methanol, the yield of purified dye is 0.5 g (21 percent), m.p. 23 l-232 C dec.

19 3-Ethyl-5-[ 3 ,5 -neopentylene-5-( 3-pyrr0linl -yl )-2,4- pentadienylidene]rhodanine 5-Acetanilidomethylene-3-ethylrhodanine (3.1 g) and l-(5,5-dimethyl-3-methylene-l-cyclohexen-l-yl)- 3-pyrroline (2.1 g) are dissolved in N,N- dimethylacetamide ml) and heated at a gentle reflux for 5 minutes. After diluting with -300 ml of boiling methanol, the mixture is allowed to stand at room temperature for 30 minutes and then the dye is collected on a filter. The yield is 1.0 g (28 percent), 219-220 C dec. 3-Ethyl-5-[5,5-dimethyl-3-(3-pyrrolin-l-yl)-2- cyclohexenylidenel-rhodanine l-(3Chl0ro-5,5-dimethyl-2-cyclohexen-1-ylidene)-3- pyrrolinium perchlorate (3.10 g), 3-ethylrhodanine (1.61 g) and triethylamine (3.1 ml) are dissolved in ethanol ml) and heated at reflux for 10 minutes. After chilling, the solid is collected on a filter and then recrystallized from pyridine/methanol. The yield of purified dye is 1.78 g (53 percent), m.p. l92193 C dec. 3-Allyl-5-[5,5-dimethyl-3-(3-pyrrolin-lyl)-2- cyclohexenyli-dene]rhodanine on: El: HIC CH Hi0 CH:

l-(3-Chloro-5,5-dimethyl-2-cyclohexen-l-ylidene)- 3-pyrrolinium perchlorate (3.10 g), 3-ethyl-1-phenyl- 2-thiohydantoin (2.2 g) are triethylamine (3.1 ml) are dissolved in ethanol (15 ml) and heated at reflux for 10 minutes. After chilling, the crude dye is collected on a filter and then recrystallized from methanol. The yield of purified dye is 1.50 g (38 percent), m.p. 2 l 9-220 C dec.

3-Ethyl-2-[4-( l ,2,5,6-tetrahydrol -pyridyl)-3,4- trimethylene-l,3-butadienyl]benzoxazolium perchlorate l-Cyclopentylidene-l ,2,5 ,6-tetrahydropyridinium perchlorate (2.7 g), 2-(2-acetanilidovinyl)-3-ethylbenzoxazolium iodide (4.3 g) and triethylamine (1.5 ml) are dissolved in acetic anhydride (20 ml) and stirred at room' temperature for 2 hours. The crude dye is collected on a filter and then recrystallized from methanol. The yield of purified dye is 0.9 g (21 percent), m.p. 214-2l5 C dec. 3-Ethyl-2-[4-( l ,2,5 ,6-tetrahydr0- l -pyridyl )-3,4- trimethylene-l ,3 butadienyllbenzothiazolium perchlorate l-Cyclopentylidenel ,2,5 ,6-tetrahydropyridinium perchlorate (2.7 g), 2-( 2-acetanilidovinyl)-3-ethylbenzothiazolium iodide (4.5 g) and triethylamine (1.5 ml) are dissolved in acetic anhydride (20 ml) and the mixture stirred at room temperature for l A hours. The crude dye is collected on a filter, rinsed with ethanol and then recrystallized twice from methanol. The yield of purified dye is 1.0 g (23 percent), m.p. 227-228 C dec. 3,3 '-Diethyl-l0,1Z-ethylene-l l-( l ,2,5,6-tetrahydrol pyridyl)-oxatricarbocyanine perchlorate 5 (37 percent), m.p. 25l-252 C dec.

3-Ethyl-5-[2-( 3-pyrrolinl -yl l -cyclopentenylmethylene]-rhodanine Cyclopentylidene-3-pyrrolinium perchlorate (2.36 g), -acetanilidovinyl-3-ethylrhodanine (3.06 g), and triethylamine (1.5 ml) are dissolved in ethanol ml) and heated at reflux for 5 minutes. After chilling, the crude dye is collected on a filter and, after one recrystallization from benzene, the yield of purified dye is 1.35 g (44 percent), m.p. l99-200 C dec. 3-Carboxymethyl-5-[2-(3pyrrolin-l-yl)-lcyclopentenylmethylene]-rhodanine, sodium salt l-(2-Anilinomethylenecyclopentylidene)-3- pyrrolinium perchlorate (3.39 g), 3-carboxymethylrhodanine (1.91 g), acetic anhydride (1.0 ml), and triethylamine (3.0 ml) are dissolved in 4-butyrolactone (15 ml) and heated at a gentle reflux for 5 minutes. A solution of sodium iodide (2.00 g) in acetonitrile (50 ml) is added and, after cooling, the crude dye is collected on a filter. After one recrystallization from N,N- dimethylacetamide/acetonitrile and another from water/acetonitrile, the yield is 0.31 g (9 percent), m.p. 257-258 C dec.

It is sometimes desirable to supersensitize the dyes employed in this invention. Preferred supersensitizers are the polynuclear aromatic compounds containing at least one sulfo group. The term polynuclear aromatic" as used herein is intended to mean 2 or more benzene rings fused together (for example, as in naphthalene, pyrene, etc) or at least 2 benzene rings or aromatic rings directly joined together (for example, as in diphenyl, terphenyl, quaterphenyl, etc) or through an aliphatic linkage. Such sulfonated derivatives can conveniently be presented by the following general formula: XIV. T-SO M wherein T represents a polynuclear aromatic group as defined above and M represents a hydrogen atom or a water-soluble cation salt group (e.g., sodium, potasslum, ammonium, triethylammonium, triethanolammonium, pyridinium, etc). Among the most useful of the sulfonated derivatives embraced by Formula XIV above are the compounds represented by the following general formula:

bOrM

wherein T, represents a 1,3,5-triazin-6-ylamino group, T, represents an aromatic group (i.e., benzene or substituted benzene) and M has the values given above.

Typical of the sulfonated derivatives of Formula XV above. wherein T, represents a 1,3,5-triazin-2-ylamino group (i.e., a 1,3.5-triazin-2-ylamino group) are .the compounds selected from those represented by the following general formula:

XVI.

N N M W FNH NH-f F 1:

I Y 01M S01 wherein M has the values given above and R R R R each represents a hydrogen atom or a substituent group, such as hydroxyl, aryloxyll (e.g., phenoxyl, otoloxyl, p-sulfophenoxyl, etc.), alkoxyl(e.g., methoxyl, ethoxyl, etc.), a halogen atom (e.g., chlorine, bromine, etc.), a heterocyclic radical (e.g., morpholinyl, piperidyl, etc.), an alkylthio group (e.g., methylthio, ethylthio, etc.), an arylthio group (e.g., phenylthio, tolylthio, etc.), a heterocyclylthio group (e.g., benzothiazylthio, etc.) an amino group, an alkylamino group (e.g., methylamino, ethylamino, propylamino, dimethylamino, diethylamino, dodecylamino, cyclohexylamino, B-hydroxyethylamino, di-B-hydroxyethylamino, B-sulfoethylamino, etc.), an arylamino group (e.g., ani' lino, 0-, mand p-anis ylamino, 0-, mand pchloroanilino, o-, mand p-toludino, o-, m-, and p carboxyanilino, hydroxyanilino, sulfonaphthylarnino, 0-, mand p-aminoanilino, p-acetamidanilino, etc.),

etc.

Compounds of Formula XVI wherein R R R and/or R each represents a heterocyclylamino group (e.g., 2-benzothiazoleamino, Z-pyridylamino, etc.) can also be used in practicing my invention.

Another group of sulfonated derivatives which are useful in practicing the invention are those represented by the following general formula:

Xvir.

wherein R is an acylamido group (e.g., acetamido,

sulfobenzzmido, 4-methoxy-3-sulfobenzamido, 2- ethoxybenzamido, 2,4-diethoxy, benzamido, ptolylamido, 4-methyl-Z-methoxybenzamido, naphthoylamino, 2-naphthoylamino, 2,4- dimethoxybenzamido, L Z-phenylbenzamido, 2-

thienylbenzamido) or a sulfo group, R represents an acylamido group (e.g., as defined by R above), or a sulfoaryl group (e.g., sulfophenyl, p-sulfodiph enyl, etc.) and R represents a hydrogen atom or a sulfo group, said compound containing at least one sulfo group.

Compounds of Formula XVI which can advantageously be employed in practicing my invention have been described in one or more of the following representative patents: U.S.:

2,171,427 Aug, 29, 1939 2,472,475 June 14, 1949 2,595,030 Apr. 29, 1952 2,660,578 Nov. 24, 1953 2,945,762 July l9, 1960 British:

595,065 Nov. 26, 1947 623,849 May 24, 1949 624,051 May 26, 1949 624,052 May 26, 1949 678,291 Sept. 3., 1952 681,642 Oct. 29. 1952 705,406 Mar. 10, 1954 The products of Formula XVl have been previously employed in the textile field, and are sold under such tradenames as Leucophor B, Calcofluor White MR, Tinopal (SP, WR, BV277, 28, GS, NG), Blancofor SC, Hiltamine (BSP, N, Sol., 6T6), and the like.

The dibenzothiophenedioxide compounds of Formula XVII have, in general, been previously described in the prior art. See, for example, US Pat. Nos. 2,573,652; 2,580,234; and 2,563,493. Further examples of the preparation of such compounds are given in J. E. Jones, J. Spence, and J.A. VanAllan, US. Pat. No. 2,937,089, issued May 17, 1960. Still other examples of compounds represented by Formula XIV above which can be used in my invention have been previously described in B. H. Carroll, J. E. Jones, and J. Spence, U.S. Pat. No. 2,950,196, issued Aug. 23, 1960. (See, in particular, the compounds of Formulas 11, Ill and [V of that patent).

Compounds selected from those of Formula XV above wherein T represents a Z-benzotriazolyl group can be prepared according to methods previously described in the prior art. See, for example, US. Pat. to Zweidler et a]. No. 2,713,057, dated July 12, 1955; Keller et al., US. Pat. No. 2,684,966, dated July 27, 1954; Zweidler et al., US. Pat. No. 2,784,197, dated Mar. 5, 1957; and Keller at al., U.S, Pat. No. 2,784,183, dated Mar. 5, 1956 A somewhat related group of compounds containing a 2-benzotriazoly1 group which can be used in this invention have been previously described in US Pat. No. 2,733,165. Such compounds are embraced by Formula [Va above.

Typical sulfonated derivatives embraced byFormulas XIV, XV and XVII an Vla above are (chemical formulas are given for various types to aid in identification):

1. a sulfonated triazolostilbene, e.g., of the type shown in U.S. Pat. No. 2,713,057.

N N HO-j j'NH-QQmCH-QNH-W W-oa N 011'! 0111 N N K Y.

4,4-di(4",6"-dihydroxy-2"-s-triazinylamino)stilbene- 2,2-disulfonic acid 3. 4,4'-bis[4-(3'-sulfoanilino)-6-amino-s-triazin-2- ylamino]-stilbene 4. Tinopal-WR, a sulfonated triazinyl stilbene 5. Tinopal-2B, a sulfonated triazinyl stilbene 6. A sulfonated triazinyl stilbene, e.g., of the type shown in US. Pat. No. 2,595,030 or British Pat. No. 595,065

7. 4,4'-bis[2-(4-sulfoanilino-2-B- hydroxyethylamino)-1,3,5-triazin-6-ylamino]stilbene-2,2'-disulfonic acid 8. 4,4-bis( 2,4-dihydroxy-l ,3 ,5-triazin-6- ylamino)dibenzyl-2,2'-disulfonic acid 9. 4,4'-bis(Z-B-hydroxyethylamino-4-anilino-1,3,5-

triazin-6-ylamino )-l ,4-distynylbenzene-2,2'- disulfonic acid 10. -methoxy-2-(4-styryl-3-sulfo)phenyl-l ,2,3-

benzotriazole sodium salt 1 l. Calcofluor White-MR, a sulfonated triazinyl stilbene 3,7-bis( 2-phenylbenzamido)-2,8-disulfodibenzothiophene-5,5-dioxide 13'. 3,7-bis(2-thienylamide)-2,8disulfodibenzothiophene dioxide sodium salt 14. 3-[4-(4-methoxy-3-sulfobenzamidophenyll-7-(4- methoxy-3-sulfobenzamide)dibenzothiophene dioxide sodium salt 15. chrysene--sulfonic acid sodium salt 16. pyrene-3-sulfonic acid sodium salt 17. Phenanthrene-3-sulfonic acid sodium salt 18. 2,3-dimethylnaphthalene-l-sulfonic acid sodium salt 19. 4-[4-phenoxy-6 (B-hydroxyethylamino)-striazin2-ylamino]4-[4-chloro-6-di(B- hyd roxyethyl )amino-s-traizin-2-ylamino -stilbene- 2,2'-disulfonic acid 20. 2,8-bis[4-(4-sulfoanilino)-6-hydroxy-s-triazin-2- ylamino] carbazole 21. 4,4'-bis(4,6-di(B-hydroxyethylamino)--s-triazin- 2-yl) benzidine-2,2-disu1fonic acid .22- 2- aurylamiaqrfi.fi-qtflulfqanifinoHem 23. 4,4'-bis 4-[4-(N,4"-sulfobenzyl-N'- ethyl) amino anilino]-6-hydroxy-s-triazin-2-ylamino stilbene2.2-disulfonic acid 24. 5-acetamido-2-(4-styryl-3-sulfo)phenyl-1,2,3-

benzotriazole sodium salt 25. 2,7-diacetamido-3,-disulfodibenzothiophene- 5,5-dioxide sodium salt 26. 4-sulfo-o-terphenyl sodium salt (Lour. Organ.

Chem., Vol. 14 (1949), pg. 163

27. pyrene-3-(4-methyl-3-sulfosytryl)ketone sodium salt 28. 3,7-bis(4-methyl-2-methoxybenzamido)-2,8-

disulfodibenzothiophene-S,5-dioxide sodium salt As can be seen above, many of the sulfonated derivatives are employed in the form of their water-soluble salts, such as alkali metal (e.g., sodium, potassium, etc.) salts, or ammonium or amine (e.g., triethylamine, triethanolamine, pyiridine, aniline, etc.) salts. By thus using these derivatives, they can be added to the emulsions in substantially neutral aqueous solutions without distrubing the pH of the emulsions.

In accordance with the practice of this invention, any reducing agent (i.e., a material capable of reducing silver halide) can be employed which supersensitizes photographic silver halide emulsions containing methine dyes of the type employed herein. Particularly'good results are obtained with dihydroxy substituted reducing agents. Typical dihydroxy compounds which can be employed in the practice of this invention are selected from the group consisting of the benzenes, gammalactones, pyronimides, tetronimides, furans and pyrroles, which contain at least two hydroxyl groups.

Typical useful dihydroxy substituted compounds which can be utilized include hydroquinone, resorcinol, pyrocatechol, 3-methylpyrocatechol, toluhydro- 25 mides; 3,4,5-trihydroxy-5,6-dihydro-pyronimides; and amino hexose reductones wherein the moiety comprising the subject reductones can be represented by the following formula wherein R and R can be an alkyl radical, preferably having one to eight carbon atoms or together the necessary atoms to make a heterocyclic radical with the nitrogen atom, preferably having a 5 to 6 atom nucleus and including a second nitrogen atom or an oxygen atom such as morpholino, piperazino, pyrrolino, pyridino, pyrimidino, piperidino and the like.

Typical suitable tetronimides, pyronimides and amino hexose reductones are set out in Table B:

TABLE B S-Phenyl-B-hydroxy tetronimide Elm-(2:04:13

CoHa- =NH 5-(4-Carboxyphenyl)-3 hydroxy tetronimide, 5-(3,4-Dimethoxyphenyl)-3-hydroxy tetronimide, 5-(n-Butyl)-3-hydroxy tetronimide 5-(2-Furyl)-3-hydroxy tetronimide (5-a-Furyl-3 ,4-dihyd roxy-2-imino-2,S-dihydrbfuran), and the like; 5,6-Diphenyl-3,4,5-trihydroxy-5,fi-dihydro-pyronimide 5,6-Di-n butyl-3,4,51trihydroxy-5,6-dihydropyronimide, 5,6-Di-morpholino-3,4,5-trihydroxy-5,-dihydropyronimide, y 5,6-(2-Sulfophenyl)3,4,5-trihydroxy5,6-dihydro pyronimide, and the like;

Dimethylamino hexose reductone Di-n-butylamino hexose reductone Di-n-hexylamino hexose reductone Morpholino hexose reductone Piperazino hexose reductone Pyrrolino hexosereductone Piperidino hexose reductone and the like.

The tetronimides an pyronimides such as mentioned above may be prepared by the methods described in British Pat. No. 782,304, Swiss Pat. No. 322,985, and in Helv. Chim. Acta, 39, 1780 (1956). The above, and still other 3-hydroxy tetronimides and 3,4,5-trihydroxy- 5,6-dihydro-pyronimides that are suitable, are disclosed in Salminen, U.S. Pat. No. 3,330,655, issued July 11, 1967.

The amino hexose reductones of the invention are derived from sugars, especially D-gluccse, although other six carbon or hexose reducing sugars such ad D- galactose, D-mannose, D-fructose, L-sorbose or the like can be used. A typical method for preparing the subject reductones comprises heating in a reaction medium substantially free of water a hcxosc reducing. sugar and an aliphatic or cyclic secondary amine in the presence of an acidic reductone-forming catalytic agent such as phosphoric acid, boric acid, acetic acid, succinic acid or the like. The removal of three mole cules of water results during the formation of the subject amino hexose reductones. The mentioned reductones and other related suitable reductones and methods for preparing such are described in Hodges, U.S. Pat. No. 2,936,308.

Emulsions containing a methine: dye of the type described above can be supersensitized with an azain dene, such as a triazaindene, a tetraazaindene or a pentaazaindene. Hydroxy and amino substituted azaindenes are especially useful. Representative useful azaindenes include those described in the following references:

Allen et al. U.S. Pat. No. 2,735,769, Feb. 21, 1956 Allen et al. U.S. Pat. No. 2,743,181, Feb. 24, 1956 Tinker et al. U.S. Pat. No. 2,835,581, May 20, 1958 Reynolds U.S. Pat. No. 2,756,147, July 24, 1956 Carroll et al. U.S. Pat. No. 2,743,180, Apr. 24, 1956 Zeitschrift fur Wiss, Phot. 47,2-28 (1952) Carroll et al. US. Pat. No. 2,716,062, Aug. 23, 1955 Allen et al. U.S. Pat. No. 2,772,164, Nov. 27, 1956 Allen et al. U.S. Pat, No. 2,713,541, July 16, 1955 Tinker U.S. Pat. No. 2,852,275,. Sept. 16, 1958 Carroll U.S. Pat. No. 2,743,180, Apr. 24, 1956 Fry U.S. Pat. No. 2,566,658-9, Sept. 4, 1951 Heimbach et al. U.S. Pat. No. 2,444,6057, July 6, 1948 Hemibach et al. U.S. Pat. No. 2,449,225-6, Sept. 14,

1948 Especially useful tetrazaindenes include those having the following formula:

in which R is an alkyl group, e.g., methyl, ethyl, propyl, butyl, etc. Some particularly useful azaindenes are listed below:

4-hydroxyrLB-hydroxy-ethyl-6-methyl-1,3 ,3a,7- tetrazaindene 5-carbethoxy-4-hydroxy-l ,3,3a,7-tetrazaindene 7-hydroxy-l,2,3,4,6'pentazaindene 2,4-dihydroxy-6-methyl- 1 ,3a,7 triazaindene 4-hyd roxy-2 y-hydroxypropyl-6*methyl-l ,3 ,3a,7- tetrazaindene i 4-hydroxy-2(4-pyridyl)-6-methyl-1,3,3a,7- tetrazaindene 4-hydroxy-6-methyll ,2,3,3a,7-pentazaindene t 5-amino-2-(p-carboxyphenyl )-7-hydroxy-l ,3,4,6- pentazaindene 2,4-dihydroxy-6-methyl-l ,3a,7-triazaindene 2,5-dimethyl-7-hydroxy'1,4,7a-triazaindene 5-amino-7-hydroxy-2-methyll ,4,7a-triazaindene 5-carboxy-4-hydroxy'l ,3 ,3a,7-tetrazaindene 1,2-bis(4-hydroxy-6-methyl-l ,3,3a,7-tetrazaindene- 5-yl(ethane 1,2,3 ,4-tetrakis(4-hydroxy-6-me:thyl-1,3,3a,7- tetraazaindene-2-yl)butane 2-amino-5-carboxy-4-hydroxy-1.,3,3a,7- tetrazaindene 4-hydroxy-6-methyl-l ,3,3a,7-tetrazaindene As noted above, azaindenes function as supersensitizer in emulsions containing various methine dyes. in some emulsions, the azaindene is advantageously used in combination with reducing agent, or preferably sulfonated organic compound supersensitizer, to produce emulsions having the best overall characteristics in terms of inherent emulsion speed, sensitized speed, low fog and storage stability.

According to the invention, one or more of the sulfonated organic compounds or one or more of the azaindenes or one or more of the reducing agents, and one or more of the methine dyes, are added separately or together to light-sensitive photographic silver halide emulsions to supersensitize the emulsions. Particularly good results are frequently obtained when both sulfonated organic compound and reducing agent are employed. In some emulsions, excellent results are obtained with the combination of an azaindene with a sulfonated organic compound supersensitizer. In other instances, it is desirable to supersensitize emulsions with methine dye and sulfonated organic compound, reducing agent and azaindene. The dyes most effectively supersensitized with the compounds described above are the cyanines, particularly the carbocyanine, dicarbocyanine and tricarbocyanine dyes. The enamine tricarbocyanine dyes described herein, such as those of Formula 11 above, are particularly effective when used with supersensitizer.

The optimum concentration of methine dye and supersensitizer can be determined in a manner well known to those skilled in the art by measuring the sensitivity of test portions of the same emulsion, each portion containing a different concentration of dye and supersensitizer or mixture of supersensitizers. As a general guideline, good results are obtained with about 100 to 2,000 mg dye per mole of silver and about 25 to 2,000 mg and preferably 50 to 1,000 mg per mole of silver of the sulfonated organic supersensitizer.

The silver halide emulsions described herein can be unwashed or washed to remove soluble salts. in the latter case the soluble salts can be removed by chillsetting and leaching or the emulsion can be coagulation washed, e.g., by the procedures described in Hewitson et a1 U.S. Pat. No. 2,618,556; Yutzy et al. U.S. Pat. No. 2,614,928; Yackel U.S. Pat. No. 2,565,418; Hart et al. U.S. Pat. No. 3,241,969; and Waller et al. U.S. Pat. No. 2,489,341.

The noble metal and sulfur sensitizers can be added to the emulsion by conventional procedures, such as those described by Smith et al. in U.S. Pat. No. 2,448,0- 60 issued Aug. 31, 1948. Generally, the sensitizers are added at the completion of Ostwald ripening and prior to final digestion. The silver halide emulsions of this invention can contain speed increasing compounds such as polyalkylene glycols, cationic surface active agents and thioethers or combinations of these as described in Piper U.S. Pat. No. 2,886,437; Chechak U.S. Pat. No. 3,046,134; Carroll et al. U.S. Pat. No. 2,944,900; and Goffe U.S. Pat. No. 3,294,540.

Silver halide emulsions of this invention can be protected against the production of fog and can be stabilized against loss of sensitivity during keeping. Suitable antifoggants and stabilizers, which can be used alone or in combination, include the thiazolium salts described in Staud U.S. Pat. N0. 2,131,038 and Allen U.S. Pat.

No. 2,694,716; the azaindenes described in Piper U.S. Pat. No. 2,886,437 and Heimbach U.S. Pat. No. 2,444,605; the mercury salts described in Allen US, Pat. No. 2,728,663; the urazoles described in Anderson U.S. Pat. No. 3,287,135; the sulfocatechols described in Kennard U.S. Pat. No. 3,236,652; the oximes described in Carroll et al. British Pat. No. 623,448; nitron; nitroindazoles; the mercaptotetrazoles described in Kendall etal. U.S. Pat. No. 2,403,927, Kennard et al. U.S. Pat. No. 3,266,897 and Luckey et a1. U.S. Pat. No. 3,397,987; the polyvalent metal salts described in Jones U.S. Pat. No. 2,839,405; the thiuronium salts described in Herz U.S. Pat. No. 3,220,839; and the palladium, platinum and gold salts described in Trivelli U.S. Pat. No. 2,556,263 and Damschroder U.S. Pat. No. 2,597,915.

Photographic elements including emulsions prepared in accordance with this invention can contain incorporated developing agents such as hydroquinones, catechols, aminophenols, 3-pyrazolidones, ascorbic acid and its derivatives, reductones and phenylenediamines, or combinations of developing agents. The developing agents can be in a silver halide emulsion and/or in another suitable location in the photographic element. The developing agents can be added from suitable solvents or in the form of dispersions as described in Yackel U.S. Pat. No. 2,592,368 and Dunn et al. French Pat. No. 1,505,778.

Silver halide grains sensitized in accordance with the invention can be dispersed in colloids that can be hardened by various organic or inorganic hardeners, alone or in combination, such as the aldehydes, and blocked aldehydes, ketones, carboxylic and carbonic acid derivatives, sulfonate esters, sulfonyl halides and vinyl sulfones, active halogen compounds, epoxy compounds, aziridines, active olefins, isocyanates, carbodiimides, mixed function hardeners and polymeric hardeners such as oxidized polysaccharides, e.g., dialdehyde starch, oxyguargum etc.

Photographic emulsions sensitized in accordance with this invention can contain various colloids alone or in combination as vehicles or binding agents. Suitable hydrophilic materials include both naturallyoccurring substances such as proteins, for example, gel atin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synthetic polymeric substances such as water soluble polyvinyl compounds, e.g., poly(vinyl-pyrrolidone) acrylamide polymers or other synthetic polymeric compounds such as dispersed vinyl compounds in latex form, and particularly thosewhich increase the dimensional stability of the photographic materials. Suitable synthetic polymers include those described, for example, in U.S. 'Pat. No. 3,142,568 of Nottorf, issued July 28, 1964; 3,193,386 of White, issued July 6, 1965; 3,062,674 of Houck, Smith and Yudelson, issued Nov. 6, 1962; 3,220,844 of Houck, Smith and Yudelson, issued Nov. 30, 1965; Ream and Fowler 3,287,289, issued Nov. 22, 1966; and Dykstra U.S. Pat. No. 3,411,911; particularly effective are those waterinsoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, those which have cross linking sites which facilitate hardening or curing and those having recurring sulfobetaine units as described in Canadian Pat. No. 774,054.

Emulsions supersensitized in accordance with this invention can be used in photographic elements which contain antistatic or conducting layers, such as layers that comprise soluble salts, e.g., chlorides, nitrates, etc., evaporated metal layes, ionic polymers such as those described in Minsk U.S. Pat. No. 2,861,056 and 3,206,312 or insoluble inorganic salts such as those described in Trevoy U.S. Pat. No. 3,428,451.

Photographic emulsions containing the supersensitizing combinations of the invention can be coated on a wide variety of supports. Typical supports include cellulose nitrate film, cellulose ester film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film and related films or resinous materials, as well as glass, paper, metal and the like. Typically, a flexible support is employed, especially a paper support, which can be partially acetylated or coated with baryta and/or an alpha-olefin polymer, particularly a polymer of an'alpha-olefin containing two to carbon atoms such as polyethylene polypropylene, ethylenebutene copolymers and the like.

Sensitized emulsions of the invention can contain plasticizers and lubricants such as polyalcohols, e.g.,

glycerin and diols of the type described in Milton U.S. Pat. No. 2,960,404; fatty acids or esters such as those described in Robijns U.S. Pat. No. 2,588,765 and Duane U.S. Pat. No. 3,121,060; and silicone resins such as those described in DuPont British Pat. No.

The photographic emulsions sensitized as described herein can contain surfactants such as saponin, anionic compounds such as the alkyl aryl sulfonates described in Baldsiefen U.S. Pat. No. 2,600,831 and amphoteric compounds such as those described in Ben-Ezra U.S. Pat. No. 3,133,816.

Photographic elements containing emulsion layers sensitized as described herein can contain matting agents such as starch, titanium dioxide, zinc oxide, silica, polymeric beads including beads of the type described in Jelley et a1. U.S. Pat. No. 2,992,101 and Lynn U.S. Pat. No. 2,701,245.

Sensitized silver halide emulsions of the invention can be utilized in photographic elements which contain brightening agents including stilbene, triazine, oxazole and coumarln brightening agents. Water soluble brightening agents can be used such as those described in Albers et al. German Pat. No. 972,067 and McFall et al. U.S. Pat. No. 2,933,390 or dispersions of brighteners can be used such as those described in Jansen German Pat. No. 1,150,274 and Oetiker et al. U.S. Pat. No. 3,406,070.

Photographic elements containing emulsion layers sensitized by the invention can be used in photographic elements which contain light absorbing materials and filter dyes such as those described in Sawdey U.S. Pat. NO. 3,253,921; Gaspar U.S. Pat. No. 2,274,782; Carroll et al. U.S. Pat. No. 2,527,583 and Van Campen U.S. Pat. No. 2,956,879. If desired, the dyes can be mordanted, for example, as described in Milton and Jones U.S. Pat. No. 3,282,699.

The sensitizing dyes (and other emulsion addenda) can be added to the photographic emulsions from water solutions or suitable organic solvent solutions, for example with the procedure described in Collins et al. U.S. Pat. No. 2,912,343; Owens et a1 U.S. Pat. NO. 3,342,605; Audran U.S. Pat. No. 2,996,287 or Johnson et al. U.S. Pat. No. 3,425,835. The dyes can be dissolved separately or together, and the separate or combined solutions can be added to a silver halide emulsion, or a silver halide emulsion layer can be bathed in the solution of dye or dyes.

Photographic emulsions of this invention can be coated by various coating procedures including dip coating, air knife coating, curtain coating, or extrusion coating using hoppers of the type described in Beguin U.S. Pat. No. 2,681,294. If desired, two or more layers may be coated simultaneously by the procedures described in Russell U.S. Pat. No. 2,761,791 and Wynn British Pat. No. 837,095.

Emulsions sensitized as described herein are useful in colloid transfer processes such as described in Yackel et al. U.S. Pat. No. 2,716,059; silver salt diffusion transfer processes such as described in Rott U.S. Pat. No. 2,352,014, Land U.S. Pat. No. 2,543,181, Yackel U.S. Pat. No. 3,020,155 and Land U.S. Pat. No. 2,861,885; color image transfer processes such as described in Rogers U.S. Pat. No. 3,087,817; 3,185,567; and 2,983,606; Weyerts U.S. Pat. No. 3,253,915, Whitmore et al. US. Pat. No. 3,227,550; 3,227,551 and 3,227,552; and Land U.S. Pat. No. 3,415,644; 3,415,645; 3,415,646; and imbiibition transfer processes as described in Minsk U.S. Pat. No. 2,882,156.

Silver halide emulsions containing the sensitizer combinations of this invention can be used in elements designed for color photography, for example, elements containing color-forming couplers such as those described in Frolich et al. U.S. Pat. NO. 2,376,679; Vittum et al. U.S. Pat. No. 2,322,027; Fierke et al. U.S. Pat- No. 2,801,171; Godowsky U.S. Pat. No. 2,698,794; Barr et al. U.S. Pat. No. 3,227,554 and Graham U.S. Pat. No. 3,046,129; or elements to be developed in solutions containing color-forming couplers such as those described in Mannes and Godowsky U.S. Pat. No. 2,252,718;Carrol et al. U.S. Pat. No. 2,592,243 and Schwan U.S. Pat. No. 2,950,970. Exposed photographic emulsions of this invention can be processed by various methods including processing in alkaline solutions containing conventional developing agents such as hydroquinones, catechols, aminophenols, 3-pyrazolidones, phenylen-ediamines, ascorbic acid derivatives, hydroxylamines, hydrazines and the like; web processing such as described in Tregillus et al. U.S. Pat. No. 3,179,517; stabilization processing as described in Yacke1 et al. Stabilization Processing of Films and PapersflPS/ijou'r'hdl, Vol. 16B, Aug. 1950: monobath processing as described in Levy Combined Development and Fixation of Photographic Images with Monobaths, Phat. Sci. and Eng, Vol. 2, No. 3, October, 1958, and Barnes et al. U.S. Pat. No. 3,392,019. If desired, the photographic emulsions of this invention can be processed in hardening developers such as those described in Allen et a1 U.S. Pat. No. 3,232,761; in roller transport processors such as those described in Russell U.S. Pat. No. 3,025,779; or by surface application processing as described in Example 3 of Kitze U.S. Pat. No. 3,418,132.

The silver halide emulsions sensitized by this inven tion can be used for making lithographic printing plates such as by the colloid transfer of undeveloped and unhardened areas of an exposed and developed emulsion to a suitable support as described in Clark et a] U.S. Pat. No. 2,763,553; to provide a relief image as described in Woodward U.S. Pat. No. 3,402,045 or Spencer U.S. Pat. No. 3,053,658; to prepare a relief printing The following examples are included for a further understanding of the invention.

EXAMPLES 1-8 A set of examples are prepared with four variables in order to illustrate optimum conditions of noble metal and sulfur sensitization of a very fine grain gelatino silver iodobromide (2.5 mole percent iodide) Lippmann emulsion of 0.05 m grain size. The four variables are (l level of noble metal sensitization, (2) level of sulfur sensitization, (3) length of time of the chemical sensitization at 65 C, and (4) the level of Dye A with which the emulsion was spectrally sensitized before coating (see structure and name below). Each emulsion is exposed for seconds to a tungsten 500W light source in an Eastman 1B Sensitometer and developed for 4 minutes in Kodak D-l9 developer. The coatings are made at approximately 250 mg silver and 600 mg gelatin per square foot on a cellulose acetate support. The results are shown in Table I below.

Example 1 shows the sensitivity of the primitive emulsion without chemical or spectral sensitization. Example 2 shows a marked decrease in speed upon gold and sulfur sensitization at levels in a range customarily used in the art. Upon spectral sensitization (Example 3), a notable speed increase is observed. In Example 4 a substantially higher level of gold sensitization compared with Example 3 gives a relative speed increase from 100 to 363, accompanied by a small increase in fog. An intermediate but still high level of gold sensitization is indicated in Examples 5 and 6 with lower levels of sulfur sensitization and dye. The relative speeds of these emulsions are high but not as high as in Example 4. Example 7 shows that an increase in sulfur sensitization actually causes a decrease in speed when compared to Example 6. The higher the gold level, the greater the speed. The speed generally varies inversely with the sulfur and the dye levels. Example 8 compared with Example 3 shows little change in speed when a lower level of dye was used. However, the speed drops substantially when the dye is omitted.

I 2H5 oizlernomso.

Dye A Anhydr0-3,9-diethyl-5,5 '-dimethoxy-3 '-(3- sulfopropyl)thiacarbocyanine hydroxide, the red sensitizer used in the examples above.

EXAMPLE 9 A series of gelatino silver iodobonomide Lippmann emulsions with varying iodide content from 0 to 18.8 mole percent is prepared. The grain size decreases as the iodide content increases. The emulsions are treated in three ways (A) given no further chemical sensitization, (8) chemically sensitized with 176 mg. sodium thiosulfate (23 mg. sulfur) plus 88 mg. potassium tetrachlorate (42 mg. gold) in the range 0 to 10 minutes at 65 C, and (C) chemically sensitized with 30 mg. sodium thiosulfate (3.9 mg. sulfur) plus 300 mg. potassium tetrachloraurate (144 mg. gold) in the range 0 to 10 minutes at 65 C. (Little change is noted within the 0 to 10 minutes time range.) All are coated with 300 mg. of Dye B per mole of silver. The results of photographic tests (conducted as in Examples l-8) are given in Table II. The above concentrations are given in mg. per mole of silver.

H2. 11,0: N-cm. H:

N on s Dye B 3-Ethyl-5-[2-( 3-pyrrolinl -yl)- l cyclopentenylmethylene]rhodanine.

The relative speeds are based on the same scale as Table l.

The data show that the speed effects of the high gold sensitization C persist throughout a wide range of iodide content of the silver iodobromide emulsion. Much smaller speed gains are obtained from the high sulfur and lower gold sensitization (Treatment B). Although some speed loss is noted in going to higher iodide conent, the bulk of the effect is attributable to the decreasing grain size of the emulsion. Results generally similar to those in Table II are obtained when the noble metal sensitizer is an equivalent amount of gold, platinum or palladium added, e.g., in the form of potassium iodoaurate, auric trichloride, potassium aurithiocyanate, a compound of the formula:

C-SAu N C Cl ammonium chloropalladate, sodium chloroplatinate, ammonium chlororuthenate or ammonium chloroiridate. Also, generally similar results to those in Table 11 are obtained when the sulfur sensitizer is added in an equivalent amount of a sulfur sensitizer other than sodium thiosulfate, such as thiourea, thiosinamine. Likewise, results generally similar to those in Table 11 are obtained when the various methine dyes referred to herein are substituted for dye B.

A series of Lippman gelatin silver bromoiodide (2.5 mole percent of the halide being iodide) emulsions are prepared and coated on a cellulose acetate support at a concentration of 250 mg. silver per square foot and 1041 mg. gelatin per square foot. The emulsions are chemically sensitized with potassium tetrachloroaurate and sodium thiosulfate, with 10 minute digestion at 65 C after addition of the chemical sensitizers. Various dyes, identified in Table T below, are added to the emulsions, which have the grain size and contain the concentration of chemical sensitizer given in the following tables. Supersensitizer A" is 4,4'-bis[4,6-bis-ochloroanilino-s-triazin-2-yl amino]-2,2'-stilbenedisulfonic acid, sodium salt in amounts of 1,000 mg. per mole of silver and Supersensitizer B (ascorbic acid) in amounts of 500 mg. per mole of silver are added as is described in the tables below. Each emulsion is exposed and developed as described in Examples 1-9 above, except that an exposure is made through Kodak Wratten Filters 35 and 28 to record the blue (365 line) exposure.

TABLE 111 Silver halide grain size 0.09; 300 mg. potassium tetrachloroaurate per mole of silver (about 150 mg. gold per mole of silver) and 30 mg. sodium thiosulfate (about 4 mg. sulfur per mole of silver): Sensiti- Mg. dye Super- Relative per mole sensiblue zation Dye of silver tizer speed Fogmaximum Control 8.0 0.07 1 450 200 0.08 535 2 569 60 0.06 495 3 818 A 182 0.16 525 4 847 55 0.06 495 5 510 200 0.06 490 Control 6.5 0.08 1 a 600 e 200 0.08 540 6 515 A 117 0.10 540 7 810 A 174 0.09 540 8 843 158 0.08 565 8 562 I48 0.08 565 9 548 105 0.11 550 10 444 i 174 0.08 535 11 556 A 14 0.06 12 663 A 200 0.08 525 13 541 A 129 0.09 525 14 569 A 158 0.08 570 15 366 A 105 0.08 540 1 I25 16 100 A+B 302 0.12 Pan 1? 125 Control 6.2 0.08 l 450 200 0.07 540 18 543 135 0.08 525 6 343 A+B 117 0.08 535 19 645 83 0.06 525 20 690 71 0.09 545 7 540 m 234 0.07 535 8 562 174 0.06 535 Control 5.9 0.06 1 450 200 0.06 540 21 794 100 0.07 515 22 820 58 0.08 525 23 480 A 43 0.08 525 24 714 129 0.08 525 9 411 A 110 0.10 545 25 246 A 71 0.06 530 10 296 245 0.08 535 26 437 A 35 0.08 Con trol 2.2 0.02 17 300 93 0.12 715 17 300 A+B 162 0.11 715 16 300 A+B 170 0.12 640 27 300 A+B 0.22 720 28 287 A+B 170 0.20 720 29 333 A+B 162 0.14 710 30 318 A+B 170 0.20 710 31 265 A+B 170 0.24 700 32 189 200 0.08 565 Control 1.4 0.08 17 300 A+B 170 0.14 720 Control 0.06 33 300 A 132 0.06 690 34 300 A 170 0.06 640 17 300 A 144 0.10 715 35 291 A 170 0.08 700 36 300 93 0.18 720 16 200 263 0.10 635 TABLE IV Silver halide grain size 0.09; 200 mg. potassium tetra chloroaurate per mole of silver (about 100 mg. gold per mole of silver) and 20 mg. sodium thiosulfate per mole of silver (about 2.6 mg. sulfur per mole of silver):

Mg. dye Super Relative Sensiti per mole sensiblue zation Dye of silver tizer speed Fogmaximum Control 4.0 0.06 17 300 A+B 174 0.08 715 32 500 200 0.06 560 TABLE V Silver halide grain size 0.05 micron; 320 mg..potassium tetrachloroaurate per mole of silver (about mg. gold per mole of silver) and 32 mg. sodium thiosulfate per mole of silver (about 4 mg. sulfur per mole of silver):

Sensitibenzimidazolinylidene )ethylidene ]-1 ethyl- 2-thiobarbituric acid 3 3-Ethyl5-[ (3-ethyl-2-benzothiazolinylidene)- ethylidene ]-2-( 2-thiazolyl)imino-4- imidazolidinone 4 1-( Z-Diethylaminoethyl )-5-[ 3-ethyl-2- benmxazolinylidene )ethylidene l-3-pheny1- Z-thiobarbituric acid 5 3,6;3,8-Di-(trimethylene)triazolinocarbocyanine perchlorate 6 3-Ethyl2-[4-(3-pyrrolin-ll)-1,3-

pentadienyl ]benzothiazo ium perchlorate pyrrolidinyD-ethyl)benzimidazolooxacarbocyanine iodide 8 1,1',3 ,3 '-Tetraethyl-5,5

bis( trifluoromelhyl benn'midazolocarbocyanine iodide 9 2-[4 (1-Piperidyl)-A"-butadienyl]-B- naphthothiazole ethiodide 3-Ethyl-5(3-methyl 2-thiamlinylideneethylidene 1 -phenyl-2-thiohydantoin l-[4-(4-morpholyl)-A butadienyllbenzothiazole ethiodide 3-Ethyl-S-l 3-methyl-2- thiawlidinylidene)ethylidenel-l-(2- morpholinoethyl)-2-thiohydantoin l-(2 Diethylaminoethyl)-5-](3-methyl2- thiazolidinylidene)ethylideneI-3-phenyl-2- thiohydantoin 3-Ethyl-5- {[3-(4-sulfobutyl-2-(3 H)-benzoxazolylidene]ethylidene}rhodanine 3-Ethyl-5-l -y-( l -pipcridyl )allylidene lrhodanine 3-Ethyl-2 -V.

{2-[2.3 .4.4u,5 ,6- hexahydro-7-l l pyrrolidinyl)- l naphthyllvinyl} {Henzoxaz'olium 2,3.4,4a.5.6

3 ,3 '-Diethyl-6,6'-dimethoxythiadicarbocyanine p-toluenesulfonate 3-Ethyl-2-[4-( l ,2,5,6-tetrahydro-l-pyridy1)- 3,4-trimethylenel ,3-butadienyl lbenzoxazolium perchlorate 2-[ 6-Ethoxycarbonyl-3-( l-pyrrolidinyl)-2- cyclohexenylidenelmethyl-3-ethylbenzothiazolium perchlorate 2,3'-Bis(3,3-diethoxypropyl)-9-ethyl-5,5'-

diphenyloxacarbocyanine bromide 2,2-Diethyloxacarbocyanine iodide 2,2'-Diethyl-8-methyloxacarbocyanine iodide 4,4'-l?ichloro-2,2',S-triethyloxacarbocyanine iodide 24 3,3'-Diethyl-4,4-dimethyl-4,5'-benzoxazolinothiacarbocyanine fluoborate 3-Ethyl-5l(3-ethyl-2-oxazolidinylidene)- ethylidenelrhodanine 4-l (-l-Ethyl-2( l )-B- naphthothiazolylidene)isopropylidene]-3- methyl- 1 p-sulfophenyD-S -pyrazolonc 3,3'-Diethyl10,l2-ethylene-l l-(4-phenyl-lpiperazinyl(oxatricarbocyanine perchlorate 3,3'-Diethyl-10,l2-ethylene-l l-( 1 ,2,3,4-

tetrahydro-Z-isoquinolyl)oxatricarbocyanine perchlorate (3,3'-D|ethyl-10,1Z-ethyIene-ll-[4-(3- phenylpropyl)piperidionolthiatricarbocyanine perchlorate 3,3'-Diethyl-l0,1Z-ethylene-l l-[4-( 3-phenylpropyl)piperidinoloxatricarbocyanine perchlorate 3,3'-Diethyl-l0,12-ethylene-1 l-( l,2,5,6-

tetrahydrol -pyridyl )oxatricarbocyanine perchlorate 3-Ethyl-5-[2-(3-pyrroline-l-yl)-lcyclopentenylmeth lene]rhodanine 3-Ethyl-5-l l-indoliny )-5,5-dimethyl-2- cyclohexenl -ylidene]ethy1idene rhodanine Anhydro-3-methyl- 9-(2-pyrrolyl)-3'-( 3-sulfopropyl)-4,5;4',5'- dibenzothiacarbocyanine hydroxide 3 ,3 '-Dietyl-7,7 -dimethoxythiadicarbocyanine iodide 2-1 l-Carboxymethyl-4-oxo-3-phenyl-2- thioxo-S-imidazolidenylidene)ethylidene]- 3-ethyll -phenyl--[ l ,3 ,3-trimethyl-2- indolinylidene)ethylideneltimidazolidinone 5-1 2-( l-Azetidinyl)- l -cyclopentenylmethylenel3-ethylrhodanine 3-Eth l-5-[(3-ethyl-2(3)-benzoxazo yidene)isopropylidene rhodanine Anhydro-l-allyl-5-chloro-3'-ethyl-5'- methoxy-3-(3-sulfopropyl)benzimidazolo oxacarbocyanine hydroxide 3-Carboxymethyl-5-[ 2-( 3-pyrrolinl -yl l cyclopcntenylmethyleneIrhodanine, sodium salt Silver halide emulsions sensitized as described herein are particularly useful in microelectronic manufacturing, e.g., solid state circuit production, and in the production of holograms. These materials are described, for example, in Kodak Data Book P-9, Kodak Films and Plates for Science and Industry, published by the Eastman Kodak Co., 1967. Emulsions employed for such purposes advantageously contain a high concentration of at least one removable and substantially photographically inert light absorbing dye, as described in Stevens British Pat. No. 1,139,062. Since these materials are generally exposed to a mercury vapor source which emits in the blue region of the spectrum at 405 nm and 436 nm and in the green region at 547 nm. it is desirable that the sliver halide exhibit high sensitivity to all three line exposures. The use of absorbing dyes to reduce image spread and produce images of exceptionally high sharpness reduces the speed and contrast of these elements as described in Kodak British Pat. No. 1,139,062. It is, therefore, desirable to increase either or both blue and green speeds. The combination of a benzothiazolinylidene-thiooxazolidinedione blue sensitizer with the oxathiazolocarbocyanine green sensitizer described in Stevens British Pat. No. 1,139,062 gives increased blue sensitivity with little or no change in green sensitivity. An increased concentration of the green sensitizer (above that which normally causes desensitization) gives an increase in green sensitivity without a substantial loss of contrast.

A particularly useful sensitizer is 3-ethyl-5-(3-ethyl- Z-benzothiazolinylidene )-2-thio-2,4-oxazolidine-dione, which can be used effectively at concentrations of about 600 to 800 mg. per mole of silver. An effective green sensitizer is 3,3-diethyl-4'-methyloxathiazolocarbocyanine iodide, which can be used effectively at 400, and preferablyv at 800 mg. per mole of silver..The combination of such sensitizers provides good blue and green speeds when the emulsion is exposed to a mercury vapor illuminant. Also highly useful is the dye 3-ethyl-5-[2-(3-pyrrolin-l-yl)-1-cyclopentenylmethylene]rhodanine which gives high contrast and a substantial speed increase on exposure to both blue and green radiation when employed in emulsions sensitized in accordance with the invention.

Good results are also obtained with cyanine, merocyanine or hemicyanine dyes having a tertiary aminoalkyl group substituted on a heterocyclic nitrogen atom of the dye, such as 6-chloro-3,3'-diethyl-l-(2- morpholinoethyl)benzimidazolooxacarbocyanine iodide. Other useful dyes and dye combinations include anhydro-9-ethyl-3 ,3 -di( 3-sulfopropyl)-4,5 ;4',5 dibenzothiacarbocyanine hydroxide, sodium salt; anhydro-3-ethyl-9-methyl-3 3-sulfobutyl )thiacarbocyanine hydroxide; anhydro-l -ethyl-3-( 3-sulfobutyl)thia- 2'-cyanine hydroxide; 3-ethyl-5-(3-ethyl-2- benzothiazolinylidene)-2-thi0-2,4-oxazolidinedione; 3,3'-diethyl-4'-methyloxathiazolocarbocyanine iodide; anhydro-3,9-diethyl-5,5-dimethoxy-3'(3-sulfopropyl)-thiacarbocyanine hydroxide; or, anhydro-9- ethyl-5 ,5 '-dimethoxy-3 ,3 -bis( 3-sulfopropyl )thiacarbocyanine hydroxide, sodium salt. 7

The following dyes provide highly useful results: 3- ethyl-2-[4,6-neopentylene-6-(4-methyl-1-piperazinyl)- 1,3,5-hexatrienyl]benzothiazolium iodide, 3-ethyl-2- [6-(4-ethoxycarbonyl-l-piperazinyl)-4,6- neopentylene-l,3,5-hexatrienyll-benzothiazolium iodide, and 3-ethyl-2-[6-(4-ethoxycarbonyl-lpiperazinyl)-4,6-neopentylene-1,3 ,S-hexatrienyl lbenzoxazolium iodide. These dyes can be used alone, or in combination with other dyes, such as 3,3-diethyl-6,6'- dimethoxythiadi carbocyanine p-toluenesulfonate. These dyes, whether used alone or in combination with other dyes, can be supersensitized, e.g., with a polynuclear aromatic compound containing at least one sulfo group (such as 4,4'-bis[4,6-bis-o-chloroanilino-striazin-Z-yl amino]-2,2'-stilbenedisulfonic acid, sodium salt), and/or a reducing agent (such as ascorbic acid).

The invention has been described in detail with particular reference to preferred embodiments thereof, but, it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. A photographic silver halide emulsion comprising light-sensitive silver halide grains having an average grain size up to about 0.2 micron; said silver halide grains being sensitized with the combination of a gold sensitizer, at a concentration of about 50 to 200 milligrams gold per mole of silver, and a sulfur sensitizer at a weight ratio of sulfur to gold of from 1:15 to 1:75; and, said silver halide being spectrally sensitized with at least one dye having one of the following formulas:

wherein Z, Z Z and 2;, each represents the nonmetallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms; each L represents a methine linkage; d, n, c, e and g each represents an integer of from one to two p and f each represents an integer of from one to three; m represents an integer of from one to five; R R R and R each represents an alkyl group or an aryl group; X and X each represents an acid anion; Q, Q, and each represents the non-metallic atoms required to complete a nitrogencontaining heterocyclic nucleus containing from to 6 atoms in the heterocyclic ring; D represents an enamine group selected from a 2,3,4,4a, 5,6-hexahydro-7-( l-pyrrolidinyl)-lmaphthyl group; a 2,6,7,7a-tetrahydro-5-( l-pyrrolidinyl)-3-indenyl group, a 3-(l-pyrrolidinyl)-2-norbornen-2yl group; a 3-(1-pyrroIidinyl)-2-indenyl group or a group having one of the following formulas:

CH: CH;

CH3 CH8 2. A photographic silver halide emulsion as defined in claim 6 wherein the light-sensitive silver halide grains have an average grain size of from about 0.02 to about 0.09 micron.

3. A photographic silver halide emulsion comprising light-sensitive silver halide grains having an average grain size up to about 0.1 micron; said silver halide grains being sensitized with the combination of a gold sensitizer, at a concentration of about 50 to 200 milligrams gold per mole of silver, and a sulfur sensitizer at a weight ratio of sulfur to gold of from 1:15 to 1:75; and, said silver halide being spectrally sensitized with a methine dye having one of the following formulas:

las:

represents a group having one of the following formu- 

2. A photographic silver halide emulsion as defined in claim 6 wherein the light-sensitive silver halide grains have an average grain size of from about 0.02 to about 0.09 micron.
 3. A photographic silver halide emulsion comprising light-sensitive silver halide grains having an average grain size up to about 0.1 micron; said silver halide grains being sensitized with the combination of a gold sensitizer, at a concentration of about 50 to 200 milligrams gold per mole of silver, and a sulfur sensitizer at a weight ratio of sulfur to gold of from 1:15 to 1: 75; and, said silver halide being spectrally sensitized with a methine dye having one of the following formulas:
 4. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3-allyl-5-(5,5-dimethyl-3-(3-pyrrolin-1-yl)-2-cyclohexenylidene)rhodanine.
 5. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3,6;3,8-di-(trimethylene)thiazolino carbocyanine salt.
 6. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentation of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3-ethyl-5-((3-methyl-2-thiazolidinylidene)ethylidene) -1-(2-morpholinoethyl)-2-thiohydantoin, said dye being supersensitized with 4,4''-bis(4,6-bis-o-chloroanilino-s-trIazin-2-yl)amino)-2,2''-stilbene -disulfonic acid, disodium salt.
 7. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a combination of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3-allyl-5-(5,5-dimethyl-3-(3-pyrrolin-1-yl)-2-cyclohexenylidene)rhodanine; 3-ethyl-2-(2-(2,3,4,4a,5,6-hexahydro-7-(1-pyrrolidinyl)-1 -naphthyl)vinyl)benzoxazolium salt; and, 3,3''-diethyl-6,6''-dimethoxythiadicarbocyanine salt, said dyes being supersensitized with 4,4''-bis(4,6-bis-o-chloroanilino-s-triazin-2-yl)amino)-2,2'' -stilbenedisulfonic acid, disodium salt and ascorbic acid.
 8. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3-ethyl-5-(2-(3-pyrrolin-1-yl)-1-cyclopentenylmethylene)rhodanine.
 9. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3-carboxymethyl-5-(2-(3-pyrrolin-1-yl)-1-cyclo-pentenylmethylene)rhodanine, sodium salt.
 10. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 l micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1:30 to 1:50; said silver halide being spectrally sensitized with 3-ethyl-2-(2-(2,3,4,4a%,"-hexahydro-7-(1-pyrrolidinyl) -1naphthyl)vinyl)benzoxazolium salt.
 11. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 5,6-dichloro-1,3''-diethyl-3-(2-(1-pyrrolidinyl) ethyl)benzimidazolo-oxacarbocyanine salt.
 12. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3-ethyl-5-(3-methyl-2-thiazolinylidene-ethylidene)-1-phenyl-2-thiohydantoin.
 13. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50; said silver halide being spectrally sensitized with 3,3''-diethyl-6,6''-dimethoxythiadicarbocyanine salt.
 14. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of a bout 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50, said silver halide being spectrally sensitized with anhydro-3,9-diethyl-5,5''- dimethoxy-3''-(3-sulfopropyl)thiocarbocyanine hydroxide.
 15. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of a bout 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50, said silver halide being spectrally sensitized with anhydro-9-ethyl-5,5''-dimethoxy-3,3''-bis(3-sulfopropyl)thiacarbocyanine hydroxide, sodium salt.
 16. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50, said silver halide being spectrally sensitized with 6-chloro-3,3''-diethyl-1-(2-moropholinoethyl)benzimidazolooxacarbocyanine salt.
 17. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50, said silver halide being spectrally sensitized with 3-ethyl-2-(4,6-neopentylene-6-(4-methyl-1-piperazinyl)-1,3,5 -hexatrienyl)benzothiazolium salt together with 3,3''-diethyl-6,6''-dimethoxythiadicarbocyanine salt.
 18. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said grains being sensitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50, said silver halide being spectrally sensitized with 3-ethyl-2-(6-(4-ethoxycarbonyl-1-piperazinyl)-4,6-neopentylene-1, 3,5-hexatrienyl)benxothiazolium salt together with 3,3''-diethyl-6,6''-dimethoxythiadicarbocyanine salt.
 19. A photographic gelatin silver halide emulsion in which the silver halide grains have an average grain size of from about 0.02 to about 0.09 micron; said graisn being seNsitized with the combination of potassium tetrachloroaurate, at a concentration of about 125 to 175 mg. gold per mole of silver, together with sodium thiosulfate at a weight ratio of sulfur to gold of from 1: 30 to 1:50, said silver halide being spectrally sensitized with 3-ethyl-2-(6-(4-ethoxycarbonyl-1-piperazinyl)-4,6-neopenthylene-1,3,5 -eexatrienyl)benzoxazolium salt together with 3,3''-diethyl-6,6''-dimethoxythiadicarbocyanine salt.
 20. In a light sensitive photographic silver halide emulsion comprising silver halide grains having a grain size up to about 0.2 micron, which grains are spectrally sensitized with a methine dye and chemically sensitized with a gold sensitizer and a sulfur sensitizer, the improvement wherein said gold sensitizer is present at a concentration of at least 50 mg. per mole of silver, and said sulfur sensitizer is present at a ratio of sulfur to gold of from 1:15 to 1:75. 